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#include "UnityPrefix.h"
#include "MeshUtility.h"
#include "Runtime/Geometry/Plane.h"
#include "Mesh.h"
using namespace std;
void CalculateNormals (StrideIterator<Vector3f> verts, const UInt32* indices, int vertexCount, int triangleCount, StrideIterator<Vector3f> outNormals)
{
std::fill_n (outNormals, vertexCount, Vector3f(0,0,0));
// Add normals from faces
int idx = 0;
for( int i = 0; i < triangleCount; ++i )
{
UInt32 index0 = indices[idx+0];
UInt32 index1 = indices[idx+1];
UInt32 index2 = indices[idx+2];
Vector3f faceNormal = CalcRawNormalFromTriangle( verts[index0], verts[index1], verts[index2] );
outNormals[index0] += faceNormal;
outNormals[index1] += faceNormal;
outNormals[index2] += faceNormal;
idx += 3;
}
// Normalize
for (StrideIterator<Vector3f> end = outNormals + vertexCount; outNormals != end; ++outNormals )
{
*outNormals = NormalizeFast (*outNormals);
}
}
float CalculateSurfaceArea (
const Matrix4x4f& objectToWorld,
const Mesh::TemporaryIndexContainer& triangles,
dynamic_array<Vector3f>& vertices)
{
// transform the vertices to world space,
// do it in place since they are a copy
for (int i = 0; i < vertices.size (); i++)
vertices[i] = objectToWorld.MultiplyPoint3 (vertices[i]);
// calculate the area
float cachedSurfaceArea = 0;
for (int i = 0; i < triangles.size () / 3; i++)
{
DebugAssert (triangles[3 * i] < vertices.size ());
DebugAssert (triangles[3 * i + 1] < vertices.size ());
DebugAssert (triangles[3 * i + 2] < vertices.size ());
Vector3f a = vertices[triangles[3 * i]];
Vector3f b = vertices[triangles[3 * i + 1]];
Vector3f c = vertices[triangles[3 * i + 2]];
cachedSurfaceArea += Magnitude (Cross (b - a, c - a)) * 0.5f;
}
return cachedSurfaceArea;
}
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